Water resistant wearable medical device

ABSTRACT

An accessory kit for use with a wearable medical device, such as a wearable defibrillator, that includes a control unit and a first plurality of electrodes electrically coupled to the control unit. The first plurality of electrodes includes a first plurality of ECG sensing electrodes and a first plurality of therapy electrodes configured to provide a defibrillating shock to a body of a patient. The accessory kit includes a waterproof enclosure configured to receive the control unit and protect the control unit during operation in a wet environment and a second plurality of electrodes that are electrically coupled to a connector configured to removably and electrically couple to the control unit. The second plurality of electrodes includes a second plurality of ECG sensing electrodes and a second plurality of therapy electrodes configured to provide a defibrillating shock to the body of the patient.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §121 as a divisionof U.S. application Ser. No. 13/311,427, filed Dec. 5, 2011 and titled“WATER RESISTANT WEARABLE MEDICAL DEVICE” which is incorporated hereinby reference in its entirety. U.S. application Ser. No. 13/311,427claims priority under 35 U.S.C. §119(e) to U.S. Provisional ApplicationSer. No. 61/423,874 titled “WATER RESISTANT WEARABLE MEDICAL DEVICE,”filed Dec. 16, 2010, which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a water resistant and/or waterproofwearable medical device, such as a defibrillator.

2. Discussion of Related Art

Cardiac arrest and other cardiac health ailments are a major cause ofdeath worldwide. Various resuscitation efforts aim to maintain thebody's circulatory and respiratory systems during cardiac arrest in anattempt to save the life of the victim. The sooner these resuscitationefforts begin, the better the victim's chances of survival. Theseefforts are expensive and have a limited success rate, and cardiacarrest, among other conditions, continues to claim the lives of victims.

To protect against cardiac arrest and other cardiac health ailments,some at-risk patients may use a wearable defibrillator, such as theLifeVest® wearable cardioverter defibrillator available from ZollMedical Corporation of Chelmsford, Mass. To remain protected, thepatient wears the device nearly continuously while going about theirnormal daily activities, while awake, and while asleep.

SUMMARY OF THE INVENTION

In accordance with one embodiment, an accessory kit for use with awearable medical device is provided. The wearable medical deviceincludes a control unit and a first plurality of electrodes electricallycoupled to the control unit, the first plurality of electrodes includinga first plurality of ECG sensing electrodes and a first plurality oftherapy electrodes configured to provide a defibrillating shock to abody of a patient. The accessory kit comprises a waterproof enclosureconfigured to receive the control unit and protect the control unitduring operation in a wet environment and a second plurality ofelectrodes. The second plurality of electrodes includes a secondplurality of ECG sensing electrodes and a second plurality of therapyelectrodes configured to provide a defibrillating shock to the body ofthe patient, the second plurality of electrodes being electricallycoupled to a connector that is configured to removably and electricallycouple to the control unit of the wearable medial device.

In accordance with one aspect of this embodiment, the connector is afirst connector, and the wearable medical device includes a connectionpod that is electrically connected to the control unit, the connectionpod being electrically connected to a second connector that isconfigured to removably and electrically connect to the first connector.In accordance with a further aspect of this embodiment, the waterproofenclosure is further configured to receive the connection pod andprotect the connection pod and the control unit during operation in thewet environment. In accordance with yet a further aspect of thisembodiment, the connection pod is electrically connected to the secondconnector by a cable, and the waterproof enclosure includes an apertureconfigured to form a waterproof seal about the cable.

In accordance with another embodiment, the second plurality ofelectrodes includes a pair of combined ECG/therapy electrodes, eachcombined ECG/therapy electrode of the pair of combined ECG/therapyelectrodes including at least one ECG sensing electrode and a therapyelectrode mounted to a common backing. In accordance with an aspect ofthis embodiment, each combined ECG/therapy electrode of the pair ofcombined ECG/therapy electrodes includes two ECG sensing electrodes andthe therapy electrode mounted to the common backing.

In accordance with another embodiment, the second plurality ofelectrodes are electrically coupled to the connector via a waterproofconnection pod. In accordance with one aspect of this embodiment, thewaterproof connection pod includes electronic circuitry that is pottedwith a waterproof potting compound, and any openings in the waterproofconnection pod are sealed with an elastomeric sealant. In accordancewith another aspect of this embodiment, the waterproof connection pod iselectrically connected to the connector by a cable, and the waterproofenclosure includes an aperture configured to form a waterproof sealabout the cable. In accordance with a further aspect of this embodiment,the second plurality of electrodes includes a pair of combinedECG/therapy electrodes, each combined ECG/therapy electrode of the pairof combined ECG/therapy electrodes including at least one ECG sensingelectrode and a therapy electrode mounted to a common backing. Inaccordance with yet a further aspect of this embodiment, each combinedECG/therapy electrode of the pair of combined ECG/therapy electrodesincludes two ECG sensing electrodes and the therapy electrode mounted tothe common backing.

In accordance with a variety of different embodiments, each respectiveelectrode of the second plurality of electrodes includes an adhesive toattach the respective electrode to the body of the patient.

In accordance with another embodiment, the first plurality of electrodesare electrically coupled to a first connection port of the control unitvia a first connection pod, and the second plurality of electrodes areelectrically coupled to the connector via a waterproof connection pod,wherein the connector is configured to removably and electrically coupleto a second connection port of the control unit that is distinct fromthe first connection port. In accordance with an aspect of thisembodiment, the waterproof connection pod includes electronic circuitrythat is potted with a waterproof potting compound, and any openings inthe waterproof connection pod are sealed with an elastomeric sealant. Inaccordance with a further aspect of this embodiment, the secondplurality of electrodes includes a pair of combined ECG/therapyelectrodes, each combined ECG/therapy electrode of the pair of combinedECG/therapy electrodes including at least one ECG sensing electrode anda therapy electrode mounted to a common backing. In accordance with yeta further aspect of this embodiment, each combined ECG/therapy electrodeof the pair of combined ECG/therapy electrodes includes two ECG sensingelectrodes and the therapy electrode mounted to the common backing,wherein at least one of the pair of combined ECG/therapy electrodesfurther includes a patient responsiveness button by which the patientcan indicate to the control unit that they are conscious.

In accordance with a further aspect of each of the above-describedembodiments, the wearable medical device includes a user interface podelectrically coupled to the control unit, and the accessory kit furthercomprises a second a waterproof enclosure configured to receive the userinterface pod and protect the user interface pod during operation in awet environment.

In accordance with another embodiment of the present invention, awearable medical device is provided. The wearable medical devicecomprises a water-resistant harness to be worn by a patient, a pluralityof ECG sensing electrodes disposed on the harness and configured tosense an ECG of the patient, a plurality of therapy electrodes disposedon the harness and configured to provide at least one defibrillatingshock to the body of the patient, and a control unit, electricallycoupled to the plurality of ECG sensing electrodes and the plurality oftherapy electrodes, configured to monitor the sensed ECG of the patient,and responsive to detection of cardiac arrhythmia of the patient, toprovide at least one defibrillating pulse of energy to at least one ofthe plurality of therapy electrodes. The control unit is housed in awaterproof case formed from a waterproof material that is sealed toprevent ingress of water during operation of the wearable medical devicein a wet environment.

In accordance with one aspect of this embodiment, the wearable medicaldevice further comprises a connection pod that electrically couples theplurality of ECG sensing electrodes and the plurality of therapyelectrodes to the control unit, wherein a body of the connection pod isformed from a waterproof material wherein any openings in the body ofthe connection pod are sealed with a waterproof sealant. In accordancewith an aspect of this embodiment, the connection pod includeselectronic circuitry, and the electronic circuitry is potted in awaterproof potting compound. In accordance with another aspect of thisembodiment, the connection pod is electrically connected to theplurality of ECG sensing electrodes and the plurality of therapyelectrodes by a removable connector. In accordance with this embodiment,the removable connector is waterproof. In accordance with anotherembodiment, the connection pod is electrically connected to the controlunit by a removable and waterproof connector. In accordance with anotherembodiment, the connection pod is permanently electrically coupled tothe control unit in a waterproof manner.

In accordance with a further aspect of the present invention, thewearable medical device can further comprise a user interface podconfigured to wirelessly communicate with the control unit, the userinterface pod being housed in a waterproof case that is sealed toprevent the ingress of water during operation of the wearable medicaldevice in a wet environment. In accordance with this embodiment, theuser interface pod includes a speaker that is sealed with awater-resistant and sound permeable material.

In accordance with another embodiment of the present invention, anaccessory kit for use with a wearable medical device is provided. Thewearable medical device includes a control unit and a first plurality ofelectrodes electrically coupled to the control unit, the first pluralityof electrodes including a first plurality of ECG sensing electrodes anda first plurality of therapy electrodes configured to provide adefibrillating shock to a body of a patient. The accessory kit comprisesa second plurality of electrodes that includes a second plurality of ECGsensing electrodes and a second plurality of therapy electrodesconfigured to provide a defibrillating shock to the body of the patient,and a waterproof connection pod electrically connected to the each ofthe second plurality of electrodes. The waterproof connection podincludes an elongated cable to electrically couple the waterproofconnection pod and the plurality of second electrodes to the controlunit, wherein the elongated cable has a length sufficient to allow thecontrol unit to remain in a dry location while also allowing freedom ofmovement of the patient in an adjacent wet environment with theplurality of second electrodes attached to the body of the patient.

In accordance with an aspect of this embodiment, the length of theelongated cable is at least three meters. In accordance with anotheraspect of this embodiment, the elongated cable is electrically coupledto the control unit by a removable connector. In accordance with yetanother aspect of this embodiment, the second plurality of electrodesincludes a pair of combined ECG/therapy electrodes, each combinedECG/therapy electrode of the pair of combined ECG/therapy electrodesincluding at least one ECG sensing electrode and a therapy electrodemounted to a common backing. In accordance with a further aspect of thisembodiment, each ECG/therapy electrode of the pair of combinedECG/therapy electrodes includes two ECG sensing electrodes and thetherapy electrode mounted to the common backing.

In accordance with at least one embodiment, the wearable medical deviceincludes a user interface pod electrically coupled to the control unit,and the accessory kit further comprises a waterproof enclosureconfigured to receive the user interface pod and protect the userinterface pod during operation in the wet environment.

In accordance with another embodiment, the wearable medical devicefurther includes a user interface pod configured to wirelesslycommunicate with the control unit, the user interface pod being housedin a waterproof case that is sealed to prevent the ingress of waterduring operation in the wet environment.

In accordance with yet another embodiment, the first plurality ofelectrodes are electrically coupled to a first connection port of thecontrol unit, and the removable connector is configured to removably andelectrically couple to a second connection port of the control unit thatis distinct from the first connection port. In accordance with an aspectof this embodiment, the second plurality of electrodes includes a pairof combined ECG/therapy electrodes, each combined ECG/therapy electrodeof the pair of combined ECG/therapy electrodes including at least oneECG sensing electrode and a therapy electrode mounted to a commonbacking. In accordance with a further aspect of this embodiment, eachcombined ECG/therapy electrode of the pair of combined ECG/therapyelectrodes includes two ECG sensing electrodes and the therapy electrodemounted to the common backing, wherein at least one of the pair ofcombined ECG/therapy electrodes further includes a patientresponsiveness button by which the patient can indicate to the controlunit that they are conscious.

In accordance with another embodiment of the present invention, awearable medical device is provided. The wearable medical devicecomprises a plurality of ECG sensing electrodes configured to sense anECG of a patient, a plurality of therapy electrodes configured toprovide at least one defibrillating shock to the body of the patient,and a control unit, electrically coupled to the plurality of ECG sensingelectrodes and the plurality of therapy electrodes. The control unit isconfigured to monitor the sensed ECG of the patient, and responsive todetection of cardiac arrhythmia of the patient, to provide at least onedefibrillating pulse of energy to at least one of the plurality oftherapy electrodes. The control unit includes a master control unit anda waterproof slave control unit, the master control unit beingphysically separable from the waterproof slave control unit. Thewaterproof slave control unit includes a plurality of capacitorsconfigured to store energy to provide the at least one defibrillatingpulse of energy to the at least one of the plurality of therapyelectrodes, and the master control unit is configured to charge theplurality of capacitors prior to physical separation from the waterproofslave control unit.

Still other aspects, embodiments, and advantages of these exemplaryaspects and embodiments are discussed in detail below. Moreover, it isto be understood that both the foregoing information and the followingdetailed description are merely illustrative examples of various aspectsand embodiments of the present invention, and are intended to provide anoverview or framework for understanding the nature and character of theclaimed aspects and embodiments. Any embodiment disclosed herein may becombined with any other embodiment in any manner consistent with atleast one of the aspects disclosed herein, and references to “anembodiment,” “some embodiments,” “an alternate embodiment,” “variousembodiments,” “one embodiment,” “at least one embodiment,” “this andother embodiments” or the like are not necessarily mutually exclusiveand are intended to indicate that a particular feature, structure, orcharacteristic described in connection with the embodiment may beincluded in at least one embodiment. The appearance of such terms hereinis not necessarily all referring to the same embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 a illustrates a wearable medical device, such as a wearabledefibrillator;

FIG. 1 b illustrates a wearable medical device, such as a wearabledefibrillator, in accordance with an embodiment of the presentinvention;

FIG. 2 a illustrates a shower kit that may be used with the wearablemedical device of FIG. 1 b in accordance with an embodiment of thepresent invention;

FIG. 2 b illustrates a shower kit that may be used with the wearablemedical device of FIG. 1 b in accordance with another embodiment of thepresent invention;

FIG. 2 c illustrates an alternative control unit that may be used with awearable medical device in accordance with an embodiment of the presentinvention;

FIG. 3 a illustrates a combined ECG/therapy electrode system for usewith the shower kit of FIG. 2 a;

FIG. 3 b illustrates a combined ECG/therapy electrode system for usewith the shower kit of FIG. 2 b;

FIG. 3 c illustrates the manner in which the ECG/therapy electrodesystem of FIGS. 3 a and 3 b may be worn by a patient;

FIG. 3 d illustrates a combined ECG/therapy electrode system for usewith the shower kit of FIG. 2 b in accordance with another embodiment ofthe present invention;

FIGS. 3 e and 3 f illustrate alternative forms of a water-resistantenclosure that may be associated with the shower kits of FIGS. 2 a and 2b;

FIG. 4 a illustrates a waterproof wearable medical device in accordancewith an embodiment of the present invention;

FIG. 4 b illustrates a waterproof wearable medical device in accordancewith another embodiment of the present invention;

FIG. 4 c illustrates a waterproof wearable medical device in accordancewith a further embodiment of the present invention;

FIG. 5 a illustrates a shower kit that may be used with the wearablemedical device of FIG. 1 b in accordance with another embodiment of thepresent invention;

FIG. 5 b illustrates a shower kit that may be used with the wearablemedical device of FIG. 1 b in accordance with a further embodiment ofthe present invention;

FIG. 6 a illustrates a control unit for use with a wearable medicaldevice in accordance with another embodiment of the present invention;and

FIG. 6 b illustrates a shower belt that may be used with the controlunit of FIG. 6 a in accordance with another aspect of the presentinvention.

DETAILED DESCRIPTION

This invention is not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the drawings. The invention iscapable of other embodiments and of being practiced or of being carriedout in various ways. Also, the phraseology and terminology used hereinis for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” “having,” “containing,”“involving,” and variations thereof herein is meant to encompass theitems listed thereafter and equivalents thereof as well as additionalitems.

As discussed above, to provide protection against cardiac arrest,patients that use a wearable medical device, such as a wearabledefibrillator, generally wear the device nearly continuously while theyare awake and while they are asleep. However, there are periods of timewhere it may not be possible or practical for them to wear the device,such as when taking a shower or bathing. During such times, the patientmay remove the device when they get undressed to take a shower or bath,and may not put the device back on until they have finished showering orbathing and drying off. During this period of time, the patient is notprotected. To minimize the amount of time in which they are notprotected, many patients spend a minimal amount of time bathing.Further, because the patient is not protected when the device is removedfrom the patient's body, physicians typically recommend that someoneremain with the patient when the device is removed, to render assistancein case of a medical emergency.

Applicants have appreciated there is need to protect patients at risk ofcardiac arrest when they are showering or bathing, or even whenswimming. To address this need, Applicants have developed a number ofdifferent embodiments of a wearable medical device, such as a wearabledefibrillator, that are water resistant, waterproof, or are designed ina manner in which certain components of the wearable medical device thatcan be compromised by contact with water or another liquid can be placedin a dry location, yet still protect the patient.

FIG. 1 a illustrates a wearable medical device, such as a LifeVest®Wearable Cardioverter Defibrillator available from Zoll MedicalCorporation of Chelmsford, Mass. As shown, the wearable medical device100 includes a harness 110 having a pair of shoulder straps and a beltthat is worn about the torso of a patient. The harness 110 is typicallymade from a material, such as cotton, that is breathable, and unlikelyto cause skin irritation, even when worn for prolonged periods of time.The wearable medical device 100 includes a plurality of ECG sensingelectrodes 112 that are attached to the harness 110 at various positionsabout the patient's body and electrically coupled to a control unit 120via a connection pod 130. The plurality of ECG sensing electrodes 112,which may be dry-sensing capacitance electrodes, are used by the controlunit 120 to monitor the cardiac function of the patient and generallyinclude a front/back pair of ECG sensing electrodes and a side/side pairof ECG sensing electrodes. It should be appreciated that additional ECGsensing electrodes may be provided, and the plurality of ECG sensingelectrodes 112 may be disposed at varying locations about the patient'sbody.

The wearable medical device 100 also includes a plurality of therapyelectrodes 114 that are electrically coupled to the control unit 120 viathe connection pod 130 and which are capable of delivering one or moretherapeutic defibrillating shocks to the body of the patient, if it isdetermined that such treatment is warranted. As shown, the plurality oftherapy electrodes 114 includes a first therapy electrode 114 a that isdisposed on the front of the patient's torso and a second therapyelectrode 114 b that is disposed on the back of the patient's torso. Thesecond therapy electrode 114 b includes a pair of therapy electrodesthat are electrically coupled together and act as the second therapyelectrode 114 b. The use of two therapy electrodes 114 a, 114 b permitsa biphasic shock to be delivered to the body of the patient, such that afirst of the two therapy electrodes can deliver a first phase of thebiphasic shock with the other therapy electrode acting as a return, andthe other therapy electrode can deliver the second phase of the biphasicshock with the first therapy electrode acting as the return. Theconnection pod 130 electrically couples the plurality of ECG sensingelectrodes 112 and the plurality of therapy electrodes 114 to thecontrol unit 120, and may include electronic circuitry. For example, inone implementation the connection pod 130 includes signal acquisitioncircuitry, such as a plurality of differential amplifiers to receive ECGsignals from different ones of the plurality of ECG sensing electrodes112 and to provide a differential ECG signal to the control unit 120based on the difference therebetween. The connection pod 130 may alsoinclude other electronic circuitry, such as a motion sensor oraccelerometer by which patient activity may be monitored.

As shown in FIG. 1 a, the wearable medical device 100 may also include auser interface pod 140 that is electrically coupled to the control unit120. The user interface pod 140 can be attached to the patient'sclothing or to the harness 110, for example, via a clip (not shown) thatis attached to a portion of the interface pod 140. Alternatively, theuser interface pod 140 may simply be held in a person's hand. The userinterface pod 140 typically includes one or more buttons by which thepatient, or a bystander can communicate with the control unit 120, and aspeaker by which the control unit 120 may communicate with the patientor the bystander. In certain models of the LifeVest® WearableCardioverter Defibrillator, the functionality of the user interface pod140 is incorporated into the control unit 120.

Where the control unit 120 determines that the patient is experiencingcardiac arrhythmia, the control unit 120 may issue an audible alarm viaa loudspeaker (not shown) on the control unit 120 and/or the userinterface pod 140 alerting the patient and any bystanders to thepatient's medical condition. The control unit 120 may also instruct thepatient to press and hold one or more buttons on the control unit 120 oron the user interface pod 140 to indicate that the patient is conscious,thereby instructing the control unit 120 to withhold the delivery of oneor more therapeutic defibrillating shocks. If the patient does notrespond, the device may presume that the patient is unconscious, andproceed with the treatment sequence, culminating in the delivery of oneor more defibrillating shocks to the body of the patient.

The control unit 120 generally includes at least one processor,microprocessor, or controller, such as a processor commerciallyavailable from companies such as Texas Instruments, Intel, AMD, Sun,IBM, Motorola, Freescale and ARM Holdings. In one implementation, the atleast one processor includes a power conserving processor arrangementthat comprises a general purpose processor, such as an Intel® PXA270processor and a special purpose processor, such as a Freescale™ DSP56311Digital Signal Processor. Such a power conserving processor arrangementis described in co-pending application Ser. No. 12/833,096, entitledSYSTEM AND METHOD FOR CONSERVING POWER IN A MEDICAL DEVICE, filed Jul.9, 2010 (hereinafter the “'096 application”) which is incorporated byreference herein in its entirety. The at least one processor of thecontrol unit 120 is configured to monitor the patient's medicalcondition, to perform medical data logging and storage, and to providemedical treatment to the patient in response to a detected medicalcondition, such as cardiac arrhythmia.

Although not shown, the wearable medical device 100 may includeadditional sensors, other than the ECG sensing electrodes 112, capableof monitoring the physiological condition or activity of the patient.For example, sensors capable of measuring blood pressure, heart rate,heart sounds, thoracic impedance, pulse oxygen level, respiration rate,and the activity level of the patient may also be provided.

FIG. 1 b illustrates a wearable medical device, such as a wearabledefibrillator in accordance with an embodiment of the present invention.The wearable medical device 100′ is generally similar in both form andfunction to the wearable medical device 100 described with respect toFIG. 1 a, and thus only the differences between the wearable medicaldevice 100′ of FIG. 1 b and the wearable medical device 100 of FIG. 1 aare described in detail herein. In accordance with a first embodiment,the user interface pod 140 is electrically coupled to the control unit120 via a removable connector 222 shown more clearly in FIG. 2 a(described in detail further below), and the connection pod 130 iselectrically coupled to the plurality of ECG sensing electrodes 112 andthe plurality of therapy electrodes 114 via a removable andwater-resistant or waterproof connector 232. In this first embodiment,the removable connector 222 permits the user interface pod 140 to bedisconnected and reconnected to the control unit 120. The connector 232includes two mating portions 232 a and 232 b that permit the connectionpod 130 to be separated from and re-attached to the harness 110, theplurality of ECG sensing electrodes 112, and the plurality of therapyelectrodes 114. As described more fully below with respect to FIG. 2 a,in this first embodiment, where the patient desires to shower or bathe,they may disconnect the user interface pod 140 from the control unit120, disconnect the connection pod 130 from the harness 110, theplurality of ECG sensing electrode 112, and the plurality of therapyelectrodes 114, and remove the harness 110. The patient may thenreconnect the user interface pod 140 to the control unit 120 andreconnect the connection pod 130 to a plurality of ECG sensingelectrodes 212 and a plurality of therapy electrodes 214 associated witha shower kit 200.

In accordance with an alternative second embodiment, both the userinterface pod 140 and the connection pod 130 are electrically coupled tothe control unit 120 via removable connectors 222, 223, respectively. Inthis second embodiment, the connector 232 is not present and theplurality of ECG sensing electrodes 112 and the plurality of therapyelectrodes 114 are directly connected to the connection pod 130. Theremovable connectors 222, 223 permit the user interface pod 140 and theconnection pod 130 to be disconnected and reconnected to the controlunit 120. As described more fully below with respect to FIG. 2 b, inthis second embodiment, where the patient desires to shower or bathe,they may disconnect the user interface pod 140 and the connection pod130 from the control unit 120, remove the harness 110, and reconnect thecontrol unit 120 to the user interface pod 140 and to a connection pod230 and a plurality of ECG sensing electrodes 212 and a plurality oftherapy electrodes 214 associated with a shower kit 200′.

FIG. 2 a illustrates a shower kit 200 that may be used with a wearablemedical device, such as the wearable medical device 100′ depicted inFIG. 1 b to permit a patient to shower or bathe while remainingprotected from possibility of cardiac arrest. As illustrated in FIG. 2a, the shower kit 200 includes a waterproof or water-resistant enclosure250 configured to receive the control unit 120 and the connection pod130. The enclosure 250 includes a water resistant closure 253 which canbe opened and sealed and through which the control unit 120 and theconnection pod 130 may be inserted into and removed from the enclosure250. The water resistant closure 253 may be a press and seal closure,similar to that of a Ziploc® seal plastic bag, a water-resistant zipper,a roll-top closure, or even an elastic ring, such as a conventionalelastic band, as the present invention is not limited to any particulartype of closure. Enclosure 250 includes a first aperture 251 throughwhich the removable connector 222 may be inserted to electrically coupleto user interface pod 140 to the control unit 120, and a second aperture252 though which the mating portion 232 a of the removable connector 232may be passed through and connected to mating portion 232 b. The firstand second apertures 251 and 252 may be surrounded by an elastomericseal that conforms to the diameter of the cable passed therethrough toprevent the ingress of water into the enclosure 250. In one embodiment,the enclosure 250 is formed from a transparent, flexible andwater-resistant material, such as a clear plastic, although othersuitable materials may be used. The use of a transparent flexiblematerial permits the patient to access any buttons 124 present on thecontrol unit 120, and permits the patient to view any messages that maybe provided on a display 121 of the control unit 120. The enclosure 250may include a strap 260 that is attached to the enclosure 250 to permitthe enclosure (with control unit and connection pod 130 sealed therein)to be worn on the patient's body during bathing, or alternatively, to behung on a hook.

The shower kit 200 also includes an enclosure 270 in which the userinterface pod 140 can be received and protected from moisture, where theuser interface pod 140 is not itself water-resistant. The enclosure 270may be formed from a transparent flexible material, such as plastic,that permits the patient to view and access any buttons present on theuser interface pod 140. The enclosure 270 may include a water resistantclosure (not shown) to prevent any ingress of moisture. Alternatively,the enclosure 270 may be sealed with tape or an elastic band. Where thewearable medical device 100′ includes a user interface pod 140′ that iswater-resistant or waterproof, the use of the enclosure 270 may beomitted. Similarly, where the functionality of the user interface pod140 is integrated into the control unit 120, such as in the LifeVest®model 4000 Wearable Cardioverter Defibrillator, the enclosure 250 mayinclude only a single aperture (i.e., the second aperture 252 throughwhich the mating portion 232 a of the removable connector is passed andconnected to mating portion 232 b).

As shown in FIG. 2 a, the shower kit 200 also includes a plurality ofECG sensing electrodes 212 and a plurality of therapy electrodes 214that are electrically coupled to the mating portion 232 b of thewaterproof or water-resistant connector 232. In accordance with anaspect of the present invention, each of the plurality of ECG sensingelectrodes 212 may be conventional ECG electrodes with an adhesivebacking that are simply directly attached to the body of the patient.Similarly, the plurality of therapy electrodes 214 may also beconventional adhesively backed electrodes that are of a sufficientdimension so as to be capable of delivering one or more defibrillatingpulses of energy to the body of the patient. The plurality of therapyelectrodes 214 includes a first therapy electrode 214 a that can beadhesively attached to the front of the patient's torso, and a secondtherapy electrode that can be adhesively attached to the back of thepatient's torso 214 b. It should be appreciated that because it may bedifficult for the patient themselves to attach the second therapyelectrode 214 b to the back of their torso, the plurality of therapyelectrodes 214 may also be placed on the front of the patient's torso atspaced apart positions, or on opposing lateral sides of the patient'storso. For example, the first therapy electrode 214 a may be placed sothat it is positioned below and approximately centered on the patient'sleft breast, and the second therapy electrode may be placed so that itis positioned above and approximately centered on the patient's rightbreast. The plurality of ECG sensing electrodes 212 could also be placedon the front of the patient's torso with an ECG sensing electrodepositioned on each side of a respective therapy electrode 214 a, 214 b.Other placements of the plurality of ECG sensing electrodes 212 and theplurality of therapy electrodes 214 may also be used.

In accordance with an aspect of the present invention, during thosetimes where the patient is not bathing, the patient may wear thewearable medical device 100′ illustrated in FIG. 1 b while awake andwhile asleep. When it is necessary or desirable to bathe, the patientmay use the shower kit 200 in the following manner to minimize theamount of time during which they are not protected from cardiac arrest.

When the patient decides to bathe, the patient removes their clothing,disconnects the connector 222 from the control unit 120 and disconnectsthe plurality of ECG sensing electrodes 112 and the plurality of therapyelectrodes 114 from the removable connector 232 and removes theconnection pod 130 from the harness 110. The patient may then remove theharness 110, insert the control unit 120 into the enclosure 250, pushthe connector 222 through the aperture 251 in the enclosure andelectrically couple it to the control unit 120. The patient may thenpush the mating portion 232 a through the aperture 252 in the enclosure250 and connect the mating portion 232 a to the mating portion 232 b sothat the connection pod 130 is electrically coupled to the plurality ofECG sensing electrodes 212 and the plurality of therapy electrodes 214.The patient would then typically attach the plurality of ECG sensingelectrodes 212 to the front and back and sides of their body, and thenattach the therapy electrodes 214 a and 214 b to the front and back oftheir body. Although the exact location of the electrodes 212, 214 mayvary, they may generally be attached to the patient's body in locationssimilar to those of the wearable medical device 100′. Where placement ofelectrodes 212, 214 in locations similar to those of the wearablemedical device 100′ is not practical or possible (e.g., due to thedexterity of the patient, or due to the lack of an available caretakerto assist in the attachment of the electrodes 212, 214), the electrodes212, 214 may be placed in other locations about the patient's body. Forexample, as discussed previously above the therapy electrodes 214 may beattached to opposing sides of anterior of the patient's body (e.g.,below the patient's left breast and above the patient's right breast)with an ECG sensing electrode 212 attached on each side of a therapyelectrode. It should be appreciated that in other embodiments, only twoECG sensing electrodes 212 may be provided.

Depending upon whether a water resistant user interface pod 140′ or anon-water resistant user interface pod 140 was used, the patient mayplace the non-water resistant user interface pod 140 into the enclosure270 and seal the enclosure. Where the functionality of the userinterface pod 140 is integrated into the control unit 120, this step maysimply be omitted. The enclosure 250 may then be sealed and the patientis now ready to bathe. Because the patient is now protected, they mayshower or bathe for as long as they would like, or as frequently asdesired.

It should be appreciated that the various steps described above may beperformed in an order different than that described above. For example,to further reduce the amount of time the patient is not protected, thepatient may get undressed and place the electrodes 212, 214 on theirbody while the wearable medical device 100′ and its associated harness110 are still in position on the patient's body. It should beappreciated that the shower kit 200 provides the patient with protectionagainst cardiac arrest while utilizing most of the components of thewearable medical device 100 of FIG. 1 a with minimal modification, andwith minimal added expense.

FIG. 2 b illustrates an alternative shower kit 200′ that may be usedwith a wearable medical device, such as the wearable medical device 100′depicted in FIG. 1 b, to permit a patient to shower or bathe whileremaining protected from the possibility of cardiac arrest. As theshower kit 200′ is similar to the shower kit 200 illustrated in FIG. 2a, only differences will be described in detail herein. As in the showerkit 200, the shower kit 200′ includes a waterproof or water-resistantenclosure 250 that is configured to receive the control unit 120 andwhich includes a water resistant closure 253 which can be opened andsealed. The enclosure 250 may again be formed from a transparent,flexible material, such as plastic, that permits a patient to view andaccess portions of the control unit 120. However, in contrast to theembodiment of FIG. 2 a, the shower kit 200′ includes a connection pod230 in addition to the plurality of ECG sensing electrodes and theplurality of therapy electrodes 214. The connection pod 230 is similarin function to the connection pod 130, and may include many of the samecomponents, such as signal acquisition circuitry, motion sensors oraccelerometers, etc. However, the connection pod 230 is specificallyconfigured to be water resistant and/or waterproof. This may be achievedin a well known manner by sealing all openings in the connection pod 230with an elastomeric or other type of waterproof sealant, usingwaterproof materials such as plastic or rubber for the body of theconnection pod 230, and by potting any electronic circuitry in theconnection pod 230 with a waterproof potting compound, such that if anymoisture were to penetrate the body of the connection pod 230, theelectronic circuitry inside would not be affected.

As in the shower kit 200 described above with respect to FIG. 2 a, theenclosure 250 of the shower kit 200′ of FIG. 2 b again includes a firstaperture 251 through which the removable connector 222 may be insertedto electrically couple the user interface pod 140 to the control unit120 (where the functionality of the user interface pod 140 is integratedinto the control unit 120, such as in the LifeVest® model 4000Cardioverter Defibrillator, aperture 251 may be omitted). The enclosure250 also includes a second aperture 252. However in this embodiment, theaperture 252 is dimensioned to receive the end of a cable that iselectrically coupled to the connection pod 230 and which includes aremovable connector 223′ that is similar to the connector 223 used toelectrically couple connection pod 130 to the control unit 120 in FIG. 1b. As in the shower kit 200, the first and second apertures 251 and 252of the enclosure 250 of shower kit 200′ may be surrounded by anelastomeric seal that conforms to the diameter of the cable passedtherethrough to prevent the ingress of water into the enclosure 250. Theenclosure 250 may also include a strap 260 that is attached to theenclosure 250 to permit the enclosure (with control unit 120 sealedtherein) to be worn on the patient's body during bathing, oralternatively, to be hung on a hook.

As in the shower kit 200, the shower kit 200′ may also include anenclosure 270 in which the user interface pod 140 can be received andprotected from moisture, where the user interface pod 140 is not itselfwater-resistant. Where the wearable medical device 100′ includes a userinterface pod 140′ that is water-resistant or waterproof, or where thefunctionality of the user interface pod 140, 140′ is integrated into thecontrol unit 120, the use of the enclosure 270 may be omitted. As in theshower kit 200, the shower kit 200′ includes a plurality of ECG sensingelectrodes 212 and a plurality of therapy electrodes 214 which may be ofthe same type as those described with respect to FIG. 2 a. However, inshower kit 200,′ these electrodes are directly attached to theconnection pod 230, rather than to a mating portion 232 b of theconnector 232 shown in FIG. 2 a.

In accordance with an aspect of the present invention, during thosetimes where the patient is not bathing, the patient may wear thewearable medical device 100′ illustrated in FIG. 1 b while awake andwhile asleep. When it is necessary or desirable to bath, the patient mayuse the shower kit 200′ in the following manner to minimize the amountof time during which they are not protected from cardiac arrest.

When the patient decides to bathe, the patient removes their clothing,disconnects the connector 222 that is electrically coupled to the userinterface pod 140, 140′ from the control unit 120 and disconnects theremovable connector 223 that is electrically coupled to the connectionpod 130 from the control unit 120. The patient may then remove theharness 110 with the connection pod 130 still attached, insert thecontrol unit 120 into the enclosure 250, push the connector 222 throughthe aperture 251 in the enclosure 250 and electrically couple it to thecontrol unit 120. The patient may then push the connector 223′ that isattached to the connection pod 230 through the aperture 252 in theenclosure 250 and connect it to the control unit 120 so that the controlunit 120 is electrically coupled to the connection pod 230, theplurality of ECG sensing electrodes 212, and the plurality of therapyelectrodes 214. The patient would then typically attach the plurality ofECG sensing electrodes 212 to the front and back and sides of theirbody, and then attach the therapy electrodes 214 a and 214 b to thefront and back of their body. Although the exact location of theelectrodes 212, 214 may vary, they may generally be attached to thepatient's body in locations similar to those of the wearable medicaldevice 100′. As described previously with respect to the embodiment ofFIG. 2 a, the electrodes 212, 214 may be placed in alternative locationson the patient's body where assistance is not available, or where thepatient lacks dexterity, and in certain embodiments, the plurality ofECG sensing electrodes 212 may include only a single pair of ECG sensingelectrodes. Depending upon whether a water resistant user interface pod140′ or non-water resistant user interface pod 140 was used, the patientmay place the non-water resistant user interface pod 140 into theenclosure 270 and seal the enclosure. The enclosure 250 may then besealed and the patient is now ready to bathe. Because the patient is nowprotected, they may shower or bathe for as long as they would like, oras frequently as desired.

It should be appreciated that the various steps described above may beperformed in an order different than that described above. For example,to further reduce the amount of time the patient is not protected, thepatient may get undressed and place the electrodes 212, 214 on theirbody while the wearable medical device 100′ and its associated harness110 are still in position on the patient's body. As with the firstembodiment, the shower kit 200′ provides the patient with protectionagainst cardiac arrest while utilizing most of the components of thewearable medical device 100 of FIG. 1 a with minimal modification, andwith minimal added expense.

FIG. 2 c illustrates a control unit 120′ in accordance with analternative embodiment of the present invention that may be used tominimize the amount of time a patient is not protected before and/orafter bathing or showering. As shown, the control unit 120′ is similarto the control unit 120 described previously with respect to FIG. 1 b,in that it includes a display 121, one or more buttons 124, andconnection ports to receive removable connectors 222 and 223 (althoughit should be appreciated that in some embodiments, the connection portto receive removable connector 222 may be omitted where thefunctionality of the user interface pod 140, 140′ is integrated into thecontrol unit 120′). In contrast to previous embodiments, the controlunit 120′ includes an additional connection port 224 that is configuredto mate with the removable connector 223′ of the shower kit 200′ of FIG.2 b. The connection port 224 permits the removable connector 223′ thatis connected to the connection pod 230 to be operatively connected tothe control unit 120′ while the connection pod 130 is still operativelyconnected to the control unit 120′. While the patient is still wearingand protected by the wearable medical device 100′, the patient mayremove their clothing, and attach the plurality of ECG sensingelectrodes 212 and the plurality of therapy electrodes 214 of the showerkit 200′ to their body. The patient can then push the connector 223′that is attached to connection pod 230 through the aperture 252 in theenclosure 250 and connect it to the connection port 224 on the controlunit 120′. The patient may then disconnect the connector 223 from thecontrol unit 120′ and remove the harness 110 from their body whileprotected by the electrodes of the shower kit 200′.

In one embodiment, the control unit 120′ can include circuitry to detectthe connection of connector 223′ and connector 223 to the control unit120′ and to automatically switch between using the plurality of ECGsensing electrodes 112 and the plurality of therapy electrodes 114 thatare connected to connection pod 130 and using the plurality of ECGsensing electrodes 212 and the plurality of therapy electrodes 214 thatare connected to connection pod 230. For example, where the connector223 is connected to the control unit 120′ and the connector 223′ issubsequently connected to connection port 224, the control unit 120′ candetect that connection and automatically switch from using the pluralityof ECG sensing electrodes 112 and the plurality of therapy electrodes114 that are connected to connection pod 130 to the plurality of ECGsensing electrodes 212 and the plurality of therapy electrodes 214 thatare connected to connection pod 230. Where the connector 223 issubsequently disconnected and reconnected to the control unit 120′, thecontrol unit 120′ can detect that connection and automatically switchfrom using the plurality of ECG sensing electrodes 212 and the pluralityof therapy electrodes 214 that are connected to connection pod 230 tousing the plurality of ECG sensing electrodes 112 and the plurality oftherapy electrodes 114 that are connected to connection pod 130.

In an alternative embodiment, the control unit 120′ may include a userinterface routine by which a user can manually select which of theconnection ports is active. For example, where connector 223 andconnector 223′ are both connected to the control unit 120′, the user mayselect which one is to be used and then remove the other connector.After showering or bathing, the patient may dry themselves off,reconnect the connector 223 to the control unit 120′, and re-attach theharness 110 in position about their body prior to changing theirselection and disconnecting the connector 223′.

In yet a further alternative embodiment, the control unit 120′ mayinclude a user interface routine that not only permits a user to selectwhich one of the connection ports is active, but to also permit each ofthe connection ports to be active simultaneously. This would allow thewearable medical device to be used as a wearable cardioverterdefibrillator that is not only capable of monitoring and protecting thepatient wearing the wearable medical device, but also permitting thewearable medical device to be used as Automatic External Defibrillator(AED) for another. For example, where the patient wearing the wearablemedical device happens upon another person that appears to be sufferinga cardiac arrhythmia, the patient may attach the electrodes 212 and 214of the shower kit 200′ to the body of the other person, and connect theconnector 223′ to the connection port 224 of the control unit 120′. Forsuch use, the wearable medical device may include a pocket or pouch inwhich the shower kit 200′ may be stored. Upon connection of theconnector 223′ to the connection port 224, the control unit 120′ maymonitor the ECG signals of both the patient and the other person, andwhere a shockable cardiac arrhythmia is detected on either the patientor the other person, the control unit 120′ may apply a defibrillatingshock to that person whose ECG signals correspond to the detectedcardiac arrhythmia. It should be appreciated that this embodiment is notlimited to the use of a shower kit that includes discrete ECG sensingelectrodes 212 and discrete therapy electrodes 214 such as that shown inFIG. 2 b, as combined ECG/therapy electrodes (described in more detailbelow with respect to FIGS. 3 a-d) could alternatively be used.

Various alterations may be made to the shower kits 200 and 200′described with respect to FIGS. 2 a and 2 b. For example, FIGS. 3 a-3 cillustrate an alternative arrangement of ECG sensing electrodes andtherapy electrodes that may be used with a wearable medical device to100′ to provide protection from cardiac arrest during showering orbathing. As shown, rather than including a plurality of discrete ECGsensing electrodes 212 and a plurality of discrete therapy electrodes214 (FIGS. 2 a and 2 b), a pair of combined ECG/therapy electrodes 313a, 313 b may be used instead. Each combined ECG/therapy electrode 313 a,313 b of the pair includes a pair of ECG sensing electrodes 312 and asingle therapy electrode 314 a or 314 b that are disposed on a commonadhesive backing 309. The combined ECG/therapy electrodes 313 a and 313b are electrically compatible with the plurality of ECG sensingelectrodes 112, 212, and the plurality of therapy electrodes 114, 214 ofFIGS. 1 a, 1 b, 2 a, and 2 b, such that they may be used with thecontrol unit 120 or 120′ without modification.

The electrode system 300 of FIG. 3 a includes a waterproof connectorportion 232 b that is electrically coupled to each of the combinedECG/therapy electrodes 313 a, 313 b and is configured to mate with theconnector portion 232 a of FIG. 2 a. Thus, the electrode system 300 ofFIG. 3 a may be included in the shower kit 200 and used instead of theelectrode system shown in FIG. 2 a. The electrode system 301 of FIG. 3 bincludes a connection pod 230 that is electrically coupled to each ofthe combined ECG/therapy electrodes 313 a, 313 b and to a removableconnector 223′ that is configured to mate with the control unit 120 or120′. The connection pod 230 and the removable connector 223′ may beidentical in form and function to those same elements described withrespect to FIG. 2 b. Thus, the electrode system 301 of FIG. 3 b may beincluded in the shower kit 200′ and used instead of the electrode systemshown in FIG. 2 b.

FIG. 3 c illustrates the manner in which the pair of combinedECG/therapy electrodes 313 a, 313 b may be worn on a patient's body. Afirst of the combined ECG/therapy electrodes 313 a may be adhered to thefront of the patient's torso, and the second of the combined ECG/therapyelectrodes 313 b (shown in dotted line form) adhered to the back of thepatient's torso so that the pair of combined ECG/therapy electrodes 313a, 313 b provides a front-to-back pair of ECG sensing electrodes 312 a,312 c, a side-to-side pair of ECG sensing electrodes 312 b, 312 d, andfront and back therapy electrodes 314 a, 314 b in a manner similar tothat of wearable medical device 100 and 100′. Although not shown in FIG.3 c, it should be appreciated that the pair of combined ECG/therapyelectrodes 313 a, 313 b may be worn on the patient's body in otherlocations. For example, ECG/therapy electrode 313 a may be positioned onone side of the patient's torso with the therapy electrode 314 aapproximately centered below one armpit, and the other ECG/therapyelectrode 313 b positioned on the other side of the patient's torso withthe therapy electrode 314 b approximately centered below the otherarmpit. Although each of the combined ECG/therapy electrodes 313 a, 313b illustrated in FIGS. 3 a-3 c is shown as including a pair of ECGsensing electrodes 312 a, 312 b, and 312 c, 312 d, it should beappreciated that in other embodiments, only a single ECG electrode maybe included in each combined ECG/therapy electrode 313 a, 313 b.

FIG. 3 d illustrates yet an alternative arrangement of ECG sensingelectrodes and therapy electrodes that may be used with a wearablemedical device to 100′ to provide protection from cardiac arrest duringshowering or bathing. As in the embodiments of FIGS. 3 a-3 c, thisembodiment again includes a pair of combined ECG/therapy electrodes 313a, 313 b that may be used instead of the plurality of discrete ECGsensing electrodes 212 and the plurality of discrete therapy electrodes214 of FIGS. 2 a and 2 b. Each combined ECG/therapy electrode 313 a, 313b of the pair again includes a pair of ECG sensing electrodes 312 and asingle therapy electrode 314 a or 314 b that are disposed on a commonadhesive backing 309. However, in this embodiment, at least one of thepair of combined ECG/therapy electrodes 313 a, 313 b further includes apatient responsiveness button 333 by which the patient can indicate tothe control unit 120′ that they are conscious in the event of a detectedcardiac arrhythmia. This embodiment is particularly well suited forthose embodiments in which this functionality is integrated on thecontrol unit 120′, rather than on the user interface pod 140, 140′. Inthe event that a cardiac arrhythmia is detected and the control unit120′ issues a warning that application of a defibrillating shock isimminent, the patient may press and hold the patient responsivenessbutton 333 to delay or withhold the treatment sequence.

The electrode system 302 of FIG. 3 d includes a water resistant and/orwaterproof connection pod 230 that is electrically coupled to each ofthe combined ECG/therapy electrodes 313 a, 313 b and to a removableconnector 223′ that is configured to mate with the connection port 224on the control unit 120′. The connection pod 230 and the removableconnector 223′ may be similar in form and function to those sameelements described with respect to FIG. 2 b. In accordance with anaspect of the present invention, the electrode system 302 of FIG. 3 d isparticularly well suited for use with the control unit 120′ describedwith respect to FIG. 2 c, where the connection port 224 need not beidentical and backwards compatible with the connection pod 130 and theplurality of ECG sensing electrodes 112 and the plurality of therapyelectrodes 114 associated with the harness 110. Thus the connection port224 may be configured to include the ability to receive a patientresponsiveness signal from the patient. The manner in which the pair ofcombined ECG/therapy electrodes 313 a, 313 b of the electrode system 302may be worn on the patient's body is similar to that described abovewith respect to FIGS. 3 a-3 d, and thus further discussion is omittedherein.

FIGS. 3 e and 3 f illustrate some additional variations that may be madeto the enclosure 250 described with respect to FIGS. 2 a and 2 b. Forexample, FIG. 3 e illustrates an enclosure 350 in the form of a belt orfanny pack that can be worn by the patient when showering. In thisembodiment, the user interface pod 140, 140′ may be attached to the beltof fanny pack for convenient access by the patient. FIG. 3 f illustratesan alternative embodiment in which the enclosure 350′ has the form of abackpack. In this embodiment, the user interface pod 140, 140′ may beattached to a shoulder strap of the backpack.

FIG. 4 a illustrates a waterproof wearable medical device, such as awearable defibrillator in accordance with another embodiment of thepresent invention. The waterproof wearable medical device 400 isgenerally similar in both form and function to the wearable medicaldevice 100 described with respect to FIG. 1 a and the wearable medicaldevice 100′ of FIG. 1 b. Accordingly, only the differences are describedin detail herein. As with the wearable medical devices 100 and 100′ ofFIGS. 1 a and 1 b, the waterproof wearable medical device 400 includes aharness 410 having a pair of shoulder straps and a belt that is wornabout the torso of the patient. The waterproof wearable medical device400 also includes a plurality of ECG sensing electrodes 412 and aplurality of therapy electrodes 414 that are electrically coupled to acontrol unit 420 via a connection pod 430. In accordance with an aspectof the present invention, the harness 410 is formed from a waterproofmaterial such as rubber or Neoprene®, although other water-resistant orwaterproof materials may be used. The connection pod 430 is similar inconstruction to the connection pod 230 described with respect to FIG. 2b, in that it is specifically configured to be waterproof. For example,any openings in the connection pod 430 are sealed with an elastomeric orother type of waterproof sealant, the body of the connection pod 430 isformed from a waterproof material, such as plastic, and any electroniccircuitry within the connection pod 430 is potted in a potting compoundso as to be unaffected by moisture. The plurality of ECG sensingelectrodes 412 and the plurality of therapy electrodes 414 may besimilar to those used in the wearable medical device 100′ and describedwith respect to FIG. 1 b (e.g., dry-sensing capacitance ECG sensingelectrodes and gelled therapy electrodes), or otherwise. Although theplurality of therapy electrodes each preferably include a gel-pack torelease an impedance reducing (i.e., electrically conductive) gel whenit is determined that one or more defibrillating shocks should beadministered to the patient, it should be appreciated that in certainenvironments, such as in the salt water of the ocean or a salt waterpool, the conductivity of the water may itself be sufficient to ensure alow impedance path between the electrodes and the patient's body.

Because waterproof materials such as rubber or Neoprene® do not breatheas well as other materials, the medical device 400 may include awaterproof connector 432, similar to that described with respect toconnector 232 of FIG. 1 b. The presence of the waterproof connector 432permits a patient to use the control unit 420 with the harness 410 andassociated components of the device 400 when showering, bathing orswimming is desired, and to use the control unit 420 with the harness110 and associated components of the device 100′ of FIG. 1 b at othertimes.

Although the control unit 420 is similar in function to the controlunits 120, 120′ described previously with respect to FIGS. 1-3, it isconstructed to be waterproof. In this regard, the body or case of thecontrol unit 420 is formed from a waterproof or water-resistantmaterial, such as plastic and sealed to withstand water. Joints in thebody or case of the control unit 420 are sealed with an elastomericsealant or other type of waterproof sealant, and any openings in thecase or body of the control unit 420 (such as the opening in the casewhere the cable that connects to connection pod 430 exits, or openingsfor buttons 124 and display 121) are sealed with o-rings or anelastomeric sealant. In further contrast to the wearable medical devicedescribed with respect to FIGS. 1 a and 1 b, the waterproof wearablemedical device 400 includes a wireless user interface pod 440 thatwirelessly communicates with the control unit 420. In this embodiment,both the wireless user interface pod 440 and the control unit 420include a wireless RF transceiver that communicate with one anotherusing a wireless communication standard and protocol that is optimizedfor low cost and shorter distance (e.g., 10 meters) RF communications,such as Bluetooth, Wireless USB, or ZigBee. It should be appreciatedthat in other embodiments, the wireless user interface pod 440 and thecontrol unit 410 may communicate with one another using communicationstandards and protocols that are capable of communicating over greaterdistances, such as Wireless Ethernet, or GSM.

Although the functionality of the wireless user interface pod 440 issimilar to that of the user interface pod 140, the wireless userinterface pod 440 is also constructed to be waterproof. Thus, forexample, the case or body of the wireless user interface pod 440 isformed from a waterproof material such as plastic, and any openings inthe case or body are sealed with o-rings or an elastomeric seal.Apertures in the case or body of the wireless user interface pod 420 fora speaker or alarm may be sealed with a water-resistant but soundpermeable material, such as GORE-TEX®. The case or body of the wirelessuser interface pod 440 may include a clip or hook and loop type fastenerto permit the user interface pod 440 to be attached to the harness 410.

FIG. 4 b illustrates a waterproof wearable medical device, such as awearable defibrillator, in accordance with another embodiment of thepresent invention. The waterproof wearable medical device 401 isgenerally similar to the waterproof wearable medical device 400 of FIG.4 a with one exception. Rather than including a removable connector 432to connect the connection pod 430 to the plurality of ECG sensingelectrodes 412 and the plurality of therapy electrodes 414, the device401 includes a removable and waterproof connector 423 that is similar tothe removable connector 223′ described with respect to FIG. 2 b, butwhich forms a water-tight seal with the control unit 420. In thisembodiment, where the patient desires to shower, bathe, swim, orotherwise immerse themselves in water, they may disconnect the controlunit 420 from the connection pod 130 of the harness 110 of the wearablemedical device 100′ and connect it instead to the connection pod 430.

FIG. 4 c illustrates a waterproof wearable medical device, such as awearable defibrillator, in accordance with yet another embodiment of thepresent invention. The waterproof wearable medical device 402 isgenerally similar to the waterproof wearable medical devices 400 and 401of FIGS. 4 a and 4 b. However, the waterproof wearable medical device402 is designed to be worn continuously by the patient, whether awake,asleep, or while showering, bathing, or swimming. As a result, theconnection pod 430 is permanently coupled to the control unit 420 andpermanently coupled to the plurality of ECG sensing electrodes 412 andthe plurality of therapy electrodes 414 in a waterproof manner.

FIG. 5 a illustrates an alternative shower kit 500 in accordance with anembodiment of the present invention in which those elements of thewearable medical device 100′ that could be compromised by contact withwater or another liquid, such as control unit 120, may be placed in asecure and dry location while the patient is showering or bathing. Theshower kit 500 is similar to the shower kit 200′ described with respectto FIG. 2 b, in that it includes a plurality of ECG sensing electrodes212 and a plurality of therapy electrodes 214 which may be similar inconstruction to the plurality of ECG sensing electrodes 212 and theplurality of therapy electrodes 214 described with respect to FIG. 2 b.The shower kit 500 also includes a connection pod 230 that is similar tothe connection pod 230 of FIG. 2 b and which is constructed to be waterresistant and/or waterproof, and a user interface pod 140, 140′. Theuser interface pod 140, 140′ may be a water resistant user interface pod140′ or a non-water resistant user interface pod 140. However, incontrast to the shower kit 200′, the cable 525 that electrically couplesthe connection pod 230 to the control unit 120 and the cable 535 thatelectrically couples the user interface pod 140, 140′ to the controlunit 120 are of a sufficient length (e.g., approximately 3 meters ormore) to permit the control unit 120 to be placed outside of the showeror bathing area in a dry location, and to remain connected whileallowing free movement of the patient, even in the event that thepatient falls down (e.g., should the patient experience cardiac arrest).As depicted, the cable 525 has a removable connector 223′ thatelectrically couples the cable 525 to the control unit 120, and thecable 535 has a removable connector 222 that electrically couples thecable 535 to the control unit 120. The connectors 223′ and 222 may beidentical to the connectors 223′ and 222 of FIG. 2 b, respectively, andneed not be water resistant. Where a non-water-resistant user interfacepod 140 is used, enclosure 270 may be used to protect the user interfacepod 140 as previously described. It should be appreciated that if thecable 535 that electrically couples the user interface pod 140, 140′ tothe control unit 120 is not of a sufficient length, a cable extender maybe provided. Although the cable extender would need to be of asufficient length to permit the control unit 120 to remain in a secureand dry location while the patient was showering, this would enable thecontrol unit 120 and the user interface pod 140, 140′ of FIG. 1 b to beused without modification.

It should be appreciated that the shower kit 500 may also be used withthe control unit 120′ described above with respect to FIG. 2 c. Forexample, the removable connector 223′ can be coupled to the connectionport 224 of the control unit 120′ while the connector 223 is stilloperatively coupled to the control unit 120′ to minimize the amount oftime that the patient is not protected. Although the plurality of ECGsensing electrodes 212 and the plurality of therapy electrodes 214 shownin FIG. 5 a are depicted as being discrete electrodes, it should beappreciated that a pair of combined ECG/therapy electrodes, such asthose depicted in FIGS. 3 a-c, may alternatively be used with anextended length cable 525 and either of control unit 120 or control unit120′. Where the control unit 120′ includes a connection port 224 that isconfigured to receive a patient responsiveness signal, a combinedECG/therapy electrode system, such as the electrode system 302 of FIG. 3d may similarly be used with an extended length cable to provide ECGsensing electrodes, therapy electrodes, and a patient responsivenessbutton 333 in a single electrode system.

FIG. 5 b illustrates an alternative shower kit 501 in accordance with anembodiment of the present invention in which those elements of thewearable medical device which could be compromised by contact with wateror another liquid, such as control unit 520, may be placed in a secureand dry location while the patient is showering or bathing. The showerkit 501 is similar to the shower kit 500 described above with respect toFIG. 5 a, in that it includes a plurality of ECG sensing electrodes 212and a plurality of therapy electrodes 214 which may be similar inconstruction to those described with respect to FIG. 2 b. In addition,the shower kit 501 includes a connection pod 230 that is similar to theconnection pod 230 of FIG. 2 b and is constructed to be water resistantand/or waterproof. As in the shower kit 500, the cable 525 thatelectrically couples the connection pod 230 to the control unit 520 isof a sufficient length (e.g., approximately 3 meters or more) to permitthe control unit 520 to be placed outside of the shower or bathing areain a dry location, and to remain connected while allowing free movementof the patient, even in the event that the patient falls down (e.g.,should the patient experience cardiac arrest). As depicted, the cable525 has a removable connector 523 that electrically couples the cable525 to the control unit 520.

In the embodiment depicted in FIG. 5 b, the control unit 520communicates wirelessly with a wireless user interface pod, such as thewaterproof wireless interface pod 440 described with respect to FIGS. 4a-c. In other respects, the control unit 520 is similar to the controlunit 120 of FIG. 1 b, and like the control unit 120, need not bewaterproof or even water resistant. Although each of the embodimentsshown in FIGS. 5 a and 5 b is shown as including two pairs of ECGsensing electrodes 212, it should be appreciated that other embodimentsmay include only a single pair of ECG sensing electrodes 212. Moreover,although the plurality of ECG sensing electrodes 212 and the pluralityof therapy electrodes 214 are shown in FIG. 5 b as being discreteelectrodes, it should be appreciated that a pair of combined ECG/therapyelectrodes such as those depicted in FIGS. 3 a-c may alternatively beused.

FIG. 6 a illustrates a control unit in accordance with a further aspectof the present invention. Although the overall functionality of thecontrol unit 600 is similar to that of the control units 120, 120′, 420,and 520 described above, that functionality is divided among differentand separable units including a first master control unit 610 and asecond slave control unit 620. As will be described in further detailbelow, the master control unit 610 is not intended for use in wetenvironments, such as a shower or bath, whereas the slave control unit620 is. For use in a wet environment, the master control unit 610 may beseparated from the slave control unit 620 and left in a secure and dryenvironment, while the slave control unit 620 remains with the patientto protect them in the event of cardiac arrest.

The master control unit 610 includes circuitry 618 that implements themain user interface for the control unit 600 and controls such aspectsas the touch screen display 621 and the user interface buttons 624. Thecircuitry 618 in the master control unit 610 also handles the primaryfunctions of arrhythmia detection and cardiac event recording for thecontrol unit 600. The master control unit 610 further includes a mainrechargeable battery pack 614 that provides power to the control unit600, and powers both the master control unit 610 and the slave controlunit 620 when the two are interconnected. The master control unit 610includes a wireless communication interface 601 for wirelesslycommunicating with the slave control unit 620 when the two units arephysically separated from one another. The wireless interface 601 mayalso be used to communicate with a wireless user interface pod, such asthe wireless user interface pod 440 described above with respect toFIGS. 4 a-c.

The slave control unit 620 includes capacitors 628 for generating andstoring a defibrillating charge, high voltage charging circuitry (notshown) for charging the capacitors 628, and circuitry for controllingthe delivery of one or more defibrillating shocks to the patient. Theslave control unit 620 also includes a smaller, rechargeable battery 622that provides power to the slave control unit 620 during those periodsof time where the slave control unit 620 is separated from the mastercontrol unit 610. In certain embodiments, the battery 622 may be capableof charging the capacitors 628 to a voltage sufficient to provide atleast one defibrillating shock. The slave control unit 620 may alsoinclude a removable and waterproof connector 623 that is similar indesign and function to the connector 423 described previously withrespect to FIG. 4 b. The slave control unit 620 is purposefully designedto be waterproof and includes a wireless communication interface 602 forcommunicating with the master control unit 610 when the two units arephysically separated. The wireless communication interfaces 601, 602 maysupport any bi-directional wireless communication standard and protocol,including but not limited to wireless USB, wireless Ethernet, ZigBee,Bluetooth, GSM, etc.

During operation in generally dry environments, the control unit 600would typically be connected to a harness similar to the harness 110depicted in FIG. 1 b, and both the master control unit 610 and the slavecontrol unit 620 would be coupled together and operate as a singlecontrol unit. However, where the patient desires to shower or bathe, thepatient would remove the harness 110 and don a shower belt, such as theshower belt 690 illustrated in FIG. 6 b. The shower belt 690 iscompletely waterproof and contains all the system elements needed tofunction as a stand-alone wearable defibrillator. For example, theshower belt 690 includes a plurality of ECG sensing electrodes 612,front and back therapy electrodes 614 a, 614 b, a waterproof connectionpod 630 which may be similar to the waterproof connection pods 230 and430 described previously, and a waterproof removable connector 623. Thewaterproof removable connector 623 may be similar to the removableconnector 423 described previously with respect to FIG. 4 b. Althoughnot shown, the shower belt 690 may include a simplified user interfacethat is integrated into the belt 690 (e.g., to allow the patient toindicate that they are conscious in response to a detected cardiacarrhythmia), or alternatively, a wireless user interface pod such as thewireless user interface pod 440 described previously with respect toFIGS. 4 a-c may be used.

After disconnecting the connection pod 130, removing the harness 110,and donning the belt 690, the patient would connect the connector 623 onthe belt 690 to the slave control unit 620 and separate the mastercontrol unit 610 from the slave control unit 620. The slave control unit620 may then be attached to the belt 690, so that all elements needed tooperate as a stand-alone wearable medical defibrillator system arelocated on the belt 690 that is attached to the patient's torso. In someembodiments, the belt 690 may include a pocket to receive the slavecontrol unit 620 to again operate as a stand-alone wearable medicaldefibrillator. During operation, the slave control unit 620 wirelesslycommunicates with the master control unit 610 which is located in a dryand secure environment (e.g., outside of the shower). Where the mastercontrol unit 610 detects arrhythmia and determines that a defibrillatingshock should be delivered, the master control unit 610 sends a messageto the slave control unit 620 to charge the capacitors 628 via thebattery 622. Once the capacitors 628 are charged to the appropriatelevel, the slave control unit 620 controls the delivery of thedefibrillating shock.

It should be appreciated that the slave control unit 620 may includeadditional circuitry to allow it to protect the patient in the eventthat communication with the master control unit 610 is not possible. Forexample, the slave control unit 620 may include circuitry to perform ECGmonitoring and arrhythmia detection, as well as capacitor charging anddefibrillating shock delivery. Such circuitry may be in addition to thecircuitry contained in the master control unit 610. In an alternativeembodiment, and in accordance with the teachings of the '096application, the slave control unit 620 can include circuitry capable ofperforming all critical functions of the wearable medical deviceincluding the monitoring of ECG information, the detection of cardiacabnormalities, and the circuitry for generating and delivering one ormore defibrillating shocks to the body of the patient. In thisembodiment, the master control unit 610 would be responsible fornon-critical functions, such as event recording, storage, and analysis,remote communication capabilities, full featured user interface support,etc.

As discussed above, in the control unit 600, the slave control unit 620includes a rechargeable battery 622 that provides power to the slavecontrol unit 620 during those periods of time in which it is separatedfrom the master control unit 610. That rechargeable battery 622 may becapable of charging the capacitors 628 to a voltage sufficient toprovide at least one defibrillating shock. However, the ability tocharge the capacitors 628 to such a voltage level may require a largerand more powerful battery than would otherwise be needed to simply powerthe circuitry of the slave control unit, thereby increasing the weightof the slave control unit 620.

In accordance with a further aspect of the present invention, thecontrol unit 600 may include the ability to charge the capacitors 628 toa voltage level sufficient to provide at least one defibrillating shockprior to separation of the master control unit 610 and the slave controlunit 620. Such a ‘shower’ mode may be selected by the patient via theuser interface of the control unit 600. Once the capacitors 628 arefully charged, the units may be separated from one another and the slavecontrol unit 620 attached to the belt 690. After the patient hasfinished showering or bathing and the master control unit 610 isreattached to the slave control unit 620, the capacitors can bedischarged. This ability to pre-charge the capacitors 628 permits asmaller, lighter weight battery to be used in the slave control unit620, thereby making it more portable.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the scope of theinvention. Accordingly, the foregoing description and drawings are byway of example only.

What is claimed is:
 1. A wearable medical device, comprising: awater-resistant harness to be worn by a patient; a plurality of ECGsensing electrodes disposed on the harness and configured to sense anECG of the patient; a plurality of therapy electrodes disposed on theharness and configured to provide at least one defibrillating shock tothe body of the patient; and a control unit, electrically coupled to theplurality of ECG sensing electrodes and the plurality of therapyelectrodes, configured to monitor the sensed ECG of the patient, andresponsive to detection of cardiac arrhythmia of the patient, to provideat least one defibrillating pulse of energy to at least one of theplurality of therapy electrodes, the control unit being housed in awaterproof case formed from a waterproof material that is sealed toprevent ingress of water during operation of the wearable medical devicein a wet environment.
 2. The wearable medical device of claim 1, furthercomprising a connection pod that electrically couples the plurality ofECG sensing electrodes and the plurality of therapy electrodes to thecontrol unit, a body of the connection pod being formed from awaterproof material, wherein any openings in the body of the connectionpod are sealed with a waterproof sealant.
 3. The wearable medical deviceof claim 2, wherein the connection pod includes electronic circuitry,and wherein the electronic circuitry is potted in a waterproof pottingcompound.
 4. The wearable medical device of claim 2, wherein theconnection pod is electrically connected to the plurality of ECG sensingelectrodes and the plurality of therapy electrodes by a removableconnector.
 5. The wearable medical device of claim 4, wherein theremovable connector is waterproof.
 6. The wearable medical device ofclaim 2, wherein the connection pod is electrically connected to thecontrol unit by a removable and waterproof connector.
 7. The wearablemedical device of claim 2, wherein the connection pod is permanentlyelectrically coupled to the control unit in a waterproof manner.
 8. Thewearable medical device of claim 2, further comprising a user interfacepod configured to wirelessly communicate with the control unit, the userinterface pod being housed in a waterproof case that is sealed toprevent the ingress of water during operation of the wearable medicaldevice in a wet environment, wherein the user interface pod includes aspeaker that is sealed with a water-resistant and sound permeablematerial.
 9. The wearable medical device of claim 2, further comprisinga user interface pod, the user interface pod being housed in awaterproof case that is sealed to prevent the ingress of water duringoperation of the wearable medical device in a wet environment.
 10. Thewearable medical device of claim 9, wherein the user interface podincludes a speaker that is sealed with a water-resistant and soundpermeable material.
 11. The wearable medical device of claim 9, whereinthe user interface pod is configured to wirelessly communicate with thecontrol unit.
 12. The wearable medical device of claim 1, furthercomprising a user interface pod, the user interface pod being housed ina waterproof case that is sealed to prevent the ingress of water duringoperation of the wearable medical device in a wet environment.
 13. Thewearable medical device of claim 12, wherein the user interface podincludes a speaker that is sealed with a water-resistant and soundpermeable material.
 14. The wearable medical device of claim 12, whereinthe user interface pod is configured to wirelessly communicate with thecontrol unit.